Configuring HTTP/2 for a LoadBalancer Ingress

Ingresses can use HTTP/2 to expose Services. Connections from the load balancer to your application use HTTP/1.X by default. If your application is capable of receiving HTTP2 requests, you can add the following field to the ingress annotation to enable the use of HTTP/2:

kubernetes.io/elb.http2-enable: 'true'

An HTTPS-compliant load balancer supports HTTP/2.
This function is available in clusters of version v1.23.13-r0, v1.25.8-r0, v1.27.5-r0, or v1.28.3-r0.
If the advanced configuration for enabling HTTP/2 or the target annotation is deleted, the ELB configuration will not be modified.

The following shows an example YAML file where an existing load balancer is associated:

apiVersion: networking.k8s.io/v1
kind: Ingress 
metadata: 
  name: ingress-test
  annotations: 
    kubernetes.io/elb.id: <your_elb_id>  # Replace it with the ID of your existing load balancer.
    kubernetes.io/elb.ip: <your_elb_ip>  # Replace it with the IP of your existing load balancer.
    kubernetes.io/elb.port: '443'
    kubernetes.io/elb.http2-enable: 'true' # Enable HTTP/2.
spec:
  tls: 
  - secretName: ingress-test-secret
  rules: 
  - host: ''
    http: 
      paths: 
      - path: '/'
        backend: 
          service:
            name: <your_service_name>  # Replace it with the name of your target Service.
            port: 
              number: 8080             # Replace 8080 with the port number of your target Service.
        property:
          ingress.beta.kubernetes.io/url-match-mode: STARTS_WITH
        pathType: ImplementationSpecific
  ingressClassName: cce

**Table 1** HTTP/2 parameters
Parameter	Mandatory	Type	Description
kubernetes.io/elb.http2-enable	No	String	Whether HTTP/2 is enabled. Request forwarding using HTTP/2 improves the access performance between your application and the load balancer. However, the load balancer still uses HTTP/1.x to forward requests to the backend server. Options: true: enabled false: disabled (default value) Note: HTTP/2 can be enabled or disabled only when the listener uses HTTPS. This parameter is invalid when the listener protocol is HTTP, and defaults to false.